No problem, let's work through this together. We're starting with 71788 and are subtracting 29723 from it.

Step 1: We'll start by subtracting the digit 3 and the borrow 0 from 8 in column 1 and get 5.
5 is the first digit of our result.

Step 2: We'll start by subtracting the digit 2 and the borrow 0 from 8 in column 2 and get 6.
6 is the next digit of our result.

Step 3: We'll start by subtracting the digit 7 and the borrow 0 from 7 in column 3 and get 0.
0 is the next digit of our result.

Step 4: We'll start by subtracting the digit 9 and the borrow 0 from 1 in column 4 and get -8.
We add -8 to 10 and get 2 as the next digit of the result.

Step 5: We'll start by subtracting the digit 2 and the borrow 1 from 7 in column 5 and get 4.
4 is the next digit of our result.

So, 71788 - 29723 = 42065.